RS-232 - RS-232 wiring diagram using DB-25 pin connectors

This cable allows to connect two DTE devices (for instance two desktops or external devices).

D25 pin connector on Side 1 D25 pin connector on Side 1
D25 pin connector on Side 2 D25 pin connector on Side 2

RS-232 DB25-1 RS-232 DB25-2
Receive Data 3 2 Transmit Data
Transmit Data 2 3 Receive Data
Data Terminal Ready 20 6+8 Data Set Ready + Carrier Detect
System Ground 7 7 System Ground
Data Set Ready + Carrier Detect 6+8 20 Data Terminal Ready
Request to Send 4 5 Clear to Send
Clear to Send 5 4 Request to Send
Note: It is necessary to jumper DSR & CD to show that another side (computer or device) is online.

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RS-232 - RS-232 related links

- If your devices use other connectors (for example, DB-9 pin) look here: RS232 to RS232 connection using DB9 connectors.
- Serial port - Serial port. Possible connections. DTE-DCE, DTE-DTE.
- RS232 port connector with all pins.